shared buffers

[Glenn Sullivan]

Hi,

In the 7.4.5 version, the code is now trying to use a much larger
value for shared_buffers. I can certainly set this to a lower number
with the -B option. However, my guestion is:

What is the performance issue with setting shared_buffers to something like 45?

In doing some timing on my system, I cannot tell any difference with 45 versus 1000.
Perhaps I am looking at the wrong performance criteria.

Thanks,
Glenn
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[Tom Lane]

Glenn Sullivan <gl************@varianinc.com> writes:

What is the performance issue with setting shared_buffers to something like 45?
In doing some timing on my system, I cannot tell any difference with 45 versus 1000.

What are you timing exactly? Almost every benchmark I've ever seen is
much happier with shared_buffers of at least a few hundred. Otherwise
you spend too much time copying data between kernel and user space.

regards, tom lane

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